7. The land

The state of the biosphere – the land

General comments on the biosphere

The biosphere as a whole is under attack, and under serious pressure.

Looking at our beautiful planet piece by piece, the key natural colours are green and brown (the forests, savannahs, river plains and deserts of the land), blue and white (the snow-capped mountains and glaciers, rivers, oceans and clouds of water), and more-or-less invisible (the air). This is how it would have looked from space only 300 years ago.

Add human activities and 300 years to this, and what do we find? A lot of green has been replaced by grey (the cities) or made paler (forests being replaced by agriculture or savannahs or deserts). The white is shrinking, and the blue is getting dirtier. The invisible is turning yellow. And at night, the peace and starlight of darkness has been replaced by the blazing of lights from our cities.

So, as planetary artists we’re a bit grimy. Some would say that this is realism – we need to change things to create a world that is habitable for us. And they would be right – to a limited extent.

But the point is that our footprint on the planet is now extremely pervasive, and even visible, at the planetary level. And we have very little space left to expand to. Which also brings up the less visible aspect from a whole-of-planet perspective – in creating living space for ourselves, we’re driving out and extinguishing other species at a phenomenal rate.

Let’s take a brief guided tour, piece by piece, and then consider whether this all matters or not.

Much of what I write in the next few chapters is drawn from the “Planetary Boundaries” course I attended in the southern summer of 2014-15. The course was based on a scientific paper which identified nine “boundaries” within which humanity can have a “safe operating space”, by not creating too many imbalances in our planetary system or degrading parts of it beyond their capacity to regenerate[i]. The safe operating space, or Planetary Boundary, is called the green zone; then there is a yellow zone of uncertainty and increasing risk; and finally there is a red zone which represents high risk.

As an example, many will be familiar with the first of the Planetary Boundaries, climate change (ie climate stability), which uses two variables to assess the situation. One of these variables is the atmospheric concentration of carbon dioxide (CO2) at the Earth’s surface, made famous by Al Gore’s presentation, in which he used a cherry-picker to trace the rapid recent rise of CO2 concentration off the top of his chart[ii].

The safe Boundary is assessed at 350 parts per million (hence the name of the activist climate organisation, 350.org); the (yellow) “zone of uncertainty” is 350-450 parts per million (ppm) and, above that, all bets are off. CO2 concentration is currently about 400 ppm, and is rising at 2-3ppm per year. So this variable is in the yellow zone of uncertainty and increasing risk (as is the other variable, a more complex assessment of energy imbalance at the top of the atmosphere).

I will illustrate states and trends in the biosphere with these nine Boundaries in the following chapters. They will follow the order of the narrative, rather than the numbering system used by the authors of the original paper.

The trends in 8 of the 9 Boundaries are sharply negative, 4 of them have already been transgressed, and 2 of these 4 are already in the red zone). The diagram below summarises the 9 Boundaries and their current states:

The land

Where to begin? The tropical forests have acted as both a major carbon sink and also a home for incredible diversity of plant and animal/bird/ insect species. They process over a quarter of the total carbon dioxide which is turned to atmospheric oxygen by natural processes, and are home to between half and three-quarters of the world’s living species. But this is changing as they shrink, and they may not even be a carbon sink any more [iii].

In the industrial era of the last 250 years, the natural tropical forests have been reduced from about 15% to 5% of the Earth’s land area. It is estimated that, at current rates of deforestation, there are only 10-15 years life left in the rainforests of Indonesia and Papua New Guinea[iv]. And the way in which these forests are being destroyed, by burning to make way for cash crops, is also increasing the rate of atmospheric CO2 concentration directly, as well as causing immediate smog and health problems for neighbouring places[v].

The non-tropical (“temperate” and boreal”) forests also play important roles in as carbon sinks and homes for species. And they are also disappearing, led by deforestation in Russia and Canada[vi], but at a slower overall rate than the tropical rain forests. Reforestation has compensated for 3-6% of the overall loss in natural forests[vii]. But, overall, non-tropical forests have reduced from about 25% of land cover to 20% since pre-industrial times.

Overall, forest cover has reduced by more than a third since pre-industrial times, from 40%+ of total land area to 27-30%. Over the last 25 years, it has been reducing at about 2% of total coverage (or 0.6% of total land area) every decade, and the rate is increasing.

Planetary Boundary 6 – land-system change – yellow zone: The related Planetary Boundary is total forest cover, which now stands at 62% of the “original” (pre-industrial) level against a safe level of 75%. Our forests as a whole are in the yellow zone, but heading rapidly towards the red zone, which is assessed as 54%. The tropical forests of Africa and Asia are well into the “red” zone, while the South American rainforest, centred in Brazil, remains “green”, for now.

And we are turning the forests to monocultural use which degrades the soil, needing more and more artificial fertilisers, and eventually having to be abandoned, at which point they might revert to forest but more likely will revert to savannah, a much more impoverished state.

The savannahs (the tropical and subtropical grasslands) are also being turned over to industrial agriculture to some extent, but the worst areas for this are the river plains and forest edges, where agriculture and then cities degrade the land. Most cities naturally develop on or adjacent to fertile land, and usually next to rivers and the sea. So, they swallow up fertile land which agriculture needs, compounding the problem of industrial monoculture by pushing it onto less naturally fertile land.

Over the last century, humanity has developed a huge agriculture industry, based on continuous cropping and monoculture – the massive ploughing, fertilising and harvesting of single crops, usually achieved by corporate purchase or annexation of forests of previously multi-crop farms, and conversion of them into huge single crop plantations.

Apart from the damage done to local ecosystems, the techniques used – deep ploughing, and inappropriate crop rotation – rapidly reduce soil fertility. One “scientific forestry” experiment in Germany a couple of centuries ago lasted about a hundred years before the land was rendered barren (without even the ploughing) [ix]. The UN Food and Agriculture Organisation estimated in 2014 that the world has only 60 years on average of useable top-soil left on its current trajectory.

And, as the soil becomes degraded, maintaining yields depend on increasing use of nitrogen and phosphorus-based fertilisers, which create a whole new set of problems, discussed under Planetary Boundary 5 in Chapter 11.

Finally, the overall food system (including production and distribution) contributes about half of all greenhouse gases directly, and half of this (ie a quarter of all emissions) comes from deforestation for agricultural purposes, and from farming itself[x]. The overall impact of our emission of greenhouse gases is discussed in Chapter 10, under Planetary Boundary 1.

In New Zealand, our agricultural and forestry industries are typical of the activities and trends described above. They are mainly monoculture and commodity-based. They are degrading larger and larger areas of naturally fertile or naturally diverse or necessarily sparse land, and there has been rapid expansion of water-intensive dairying into dry provinces like Canterbury and Central Otago.

A recent report by New Zealand’s Environment Ministry showed a 28% increase in land area used for dairy farming between 2002 and 2012, accompanied by serious soil damage through compaction on 80% of dairy farms, and a 29% increase in the use of nitrogen as fertiliser[xi] between 1990 and 2012. The land itself is being degraded and, downstream, water quality and biodiversity are being compromised.

Apparently about a quarter of the Earth’s farmland is now seriously degraded[xii] and 40% of the arable land is now at risk of being turned to desert[xiii]. In China, in 2008, the People’s Daily reported that 18% of its land has reverted to desert[xiv].

Rural areas are being abandoned for the cities, partly for the potential increase in income, and partly because corporations are buying up the agricultural land and farming it with machines, leaving the previous owners little option but to try to find income in the larger towns and cities. And many cities are hosting larger and larger slum areas, where the inhabitants scratch out a precarious living[xv].

The expansion of cities and agriculture has also been disastrous for our wetlands. These are the natural sinks for excess water and some forms of pollution, and are critical to a sustainable ecology. Surface flooding in agricultural areas and cities can often be linked back to the disappearance of adjacent wetlands, which are also, like the tropical forests, home to a disproportionate diversity of life.

Yet they are disappearing, and in many places have disappeared. A recent study estimates total loss of at least 55%, and perhaps as much as 80%+, of wetlands worldwide in the last 200-300 years[xvi]. And the rate of loss is still increasing.

The requirements of resource mining and manufacture are also degrading the land from which and on which they are operating, but their most significant impacts are from their production and use, rather than their direct impact on the land – more on this in Chapter 12, on Planetary Boundaries 8 and 9.

Humanity’s use of land illustrates my point that “It’s not just about climate change”. While the reduction in forests contributes directly to climate change, it also reduces biodiversity (which will be covered in Chapter 11) and degrades the land’s capacity in general, as do industrial agriculture and the loss of wetlands. The trends in all are negative, and our dominant agricultural methods are unsustainable (this aspect is covered in more depth in Chapter 36).

Oh well, if the land can’t sustain us properly, we can always catch fish to survive, right?